A bubble level, spirit level or simply a spirit is an instrument designed to indicate whether a surface is horizontal (level) or vertical (plumb). Bubble Level app is handy, accurate, simple to use and incredibly useful tool for your Android device. A traditional modern level meter has a slightly curved glass tube which is incompletely filled with a liquid, usually a colored spirit or alcohol, leaving a bubble in the tube. At slight inclinations the bubble travels away from the center position